/*
 *    Copyright 2009-2010 The Rocoto Team
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package com.googlecode.rocoto.simpleconfig;

import java.util.Map;

/**
 * 
 *
 * @author Simone Tripodi
 * @version $Id: KeyAppender.java 407 2010-06-05 12:17:26Z simone.tripodi $
 */
final class KeyAppender implements Appender {

    private final String key;

    private final String toString;

    public KeyAppender(final String key) {
        this.key = key;
        this.toString = "${" + this.key + "}";
    }

    public void append(StringBuilder buffer, Map<String, String> configuration) {
        String value = configuration.get(this.key);
        if (value != null) {
            buffer.append(value);
        } else {
            buffer.append(this.toString);
        }
    }

    @Override
    public String toString() {
        return this.toString;
    }

}
